1. Field of Invention
This invention relates generally to ground anchors and in particular to tent pegs or stakes that are used to anchor tents and guy ropes to the ground and to ground or mooring anchors for recreational watercraft, off-road vehicles, and light aircraft.
2. Prior-Art—Tent Stakes
Prior-art tent and guy rope stakes have generally taken the shape of large nails or pegs. They normally secure a tent at two or more places. Some hold the edges of the tent against the ground, and others anchor guy ropes attached to poles at distal ends of the tent. The stakes at the tent's edge are driven nearly vertically into the ground. The guy anchor stakes are driven into the ground at an angle roughly perpendicular to the axis of the rope, typically about 45 degrees. While these stakes successfully secure a tent in mild weather conditions, they are easily dislodged if the tent is exposed to wind or other disturbances. The force of the wind or other disturbance can exert a force that is the reverse the insertion path of stakes at the tent's edge and thus pull them out of the ground. Guy ropes produce a moment of torque around the guy anchor stake's upper end, causing it to rotate and/or bend and tear through the ground. This occurs because, although the lower end of the stake is generally buried in solid soil, the top end, which bears the majority of the load or pull, is in less-compacted soil. As the size and weight of the tent increases, wind load and other forces render the holding force of prior-art stakes insufficient.
In U.S. Pat. No. 5,713,546 (1998), Auspos teaches a foldable holder for beverage containers and other items. The holder comprises a horizontal tray pivotally attached to a stake. In use, the tray is raised to a level position, and the stake is driven vertically into the ground. The tray remains supported above the ground at a convenient height for temporary storage of drinks and other items. For carrying and storage, the tray is folded to a position against the stake. While this apparatus is useful, it has no structure intended for securing a tent edge or guy rope. It is intended only for holding drinks and other items.
Various other ground anchors are known, but these also have poor holding power and other disadvantages, including large size, unwieldiness due to plural tines, and/or a complicated construction.
3. Prior Art—Anchors
Ground or mooring anchors are analogous to tent stakes and are used to anchor a vessel floating in the water to a beach or the like.
Most recreational watercraft, from small dinghies to pleasure craft of up to approximately 15 meters in length, carry one or more stern or sea anchors designed to engage a sea bed. In sheltered waters, it is possible to anchor such craft adjacent to water's edge with the bow anchor secured to the sea bed and a stern or mooring anchor embedded in the sand of the beach and connected to the stem by a hawser, e.g., of hemp or plastic.
The stem or mooring anchor is positioned on the beach some distance from the water's edge and thus is usually is elevated above the water. Thus the angle between the hawser and the ground or water is generally very small. Even though the angle is small, most anchors, such as those sold under the trademarks Danforth by Tie-Down Engineering of Atlanta, Ga., CQR by Lewmar of the U.K., and the like, do not have effective holding power in loose sand. Even though the tension applied to a hawser due to wave or wash action is only of the order of about 5 kg, the constant tugging and release of tugging force can loosen or pull out and drag even a heavy anchor over the surface.
The above anchoring and fixing of vessels is a well-studied problem; thus there have been many attempts to solve the above problems developments in this field.
Lewis, in U.S. Pat. No. 298,867 (1884), similarly shows an anchor comprising a tine that pivots inside and out of a bifurcated shank (FIGS. 2-3). Latham, in U.S. Pat. No. 57,339 (1866), shows an anchor comprising three tines pivotally attached to a bifurcated shank (FIGS. 1-2). Spedden, in U.S. Pat. No. 347,972 (1886), shows an anchor comprising a fluke pivotally attached to a top-plate and a bifurcated shank (FIGS. 3-4). McDougall, in U.S. Pat. No. 445,816 (1890), shows a blade pivotally attached to a bifurcated member, which is in turn attached to a hawser. Starr, in U.S. Pat. No. 493,901 (1892), show a sea anchor comprising a fluke pivotally attached to a top-plate (crown A) and a bifurcated shank (FIGS. 1-2).
Bunje, in U.S. Pat. No. 657,263 (1899), shows a mooring anchor comprising a plurality of tines attached to a square block. However it can pull out easily since it doesn't have a compression or stabilizer plate. Duncanson, in U.S. Pat. No. 730,009 (1902), shows an anchor comprising two tines pivotally attached to a shank (FIGS. 1-2). Neal, in U.S. Pat. No. 957,621 (1909), shows a similar anchor with several blades in the same configuration.
Myers, in U.S. Pat. No. 1,497,693 (1921), discloses an anchor comprising another fluke attached to a bifurcated shank, quite similar to those of several earlier patents described above. A crown (FIG. 6) in normal operation digs into the sea floor, mainly for the purpose of assisting the attached fluke to quickly rotate into position. Bowers, in U.S. Pat. No. 3,505,969 (1968), shows an anchor comprising two flukes pivotally attached to a base plate (FIGS. 1 & 3). Sandberg, in U.S. Pat. No. 4,224,892 (1980), shows a sea anchor. However, the projections used to engage the sea floor have a blunt shape and relatively short length that provides relatively little resistance to forces exerted by the hawser. The main advantage of this anchor seems to be its foldability for easy storage.
Eberline, in U.S. Pat. No. 4,545,318 (1984), shows an anchor comprising four tines and a pivoting plate (FIGS. 1 & 2). The tines extend from the plate's edges. Eberline's is not buried in the sand. Its operation is actuated by the presence of a sea floor obstruction of suitable size; in absence of such an obstruction the anchor will not hold. Danieli, in U.S. Pat. No. 4,756,128 (1987), discloses a ground anchor (FIG. 1) with stabilizing and compression plates and an attachment means for a hawser (FIG. 1). It has only a single spike. Fisher, in U.S. Pat. No. 4,732,105 (1988), shows another sea anchor with several flukes; however it has poor resistance to hawser tension when used as a mooring anchor.
Johnson, in U.S. Pat. No. 5,431,123 (1994), describes an anchoring apparatus having a body which is secured to the ground surface by a rod driven through an aperture in the body. A driving device with a hawser attachment mechanism is used as a handle to drive a rod (optionally with a spade-like compression plate) into sand. A loop-like member at the end of the driving device is then slipped over the protruding rod, thereby indirectly securing the hawser to the rod. It has two moving parts, 25 and 27. If these become jammed or weakened through wear or the presence of foreign matter they could render the apparatus inoperative. Its rather complex design makes it somewhat costly to manufacture.
Militello, in published patent application 2003/0024460, shows a beach anchor comprising a triangular member with a hole for a hawser and a hand hold for facilitating insertion into the beach. However this design has relatively low holding ability due to its simple design and since its hawser hole is too low for the anchor to be pushed in deeply.
Some of the foregoing patents involve pivoting flukes. These seem to suffer from the disadvantage that sand, rocks, or other material stirred up from the sea floor can become jammed in the pivoting mechanism and cause the anchor to lock up.
All of these anchors are relatively complicated and/or have relatively poor resistance to hawser tension and thus are not maximally effective in mooring a vessel, or are subject to entanglement or breakage, or have other disadvantages that make them less than optimally suitable for use as a mooring anchor.
A related area of prior art is that where ropes and lines are connected to stakes and other anchoring devices for attaching objects to the ground.
Mazur, in U.S. Pat. No. 2,870,884 (1957), shows a ground anchoring device in which three spikes are driven through apertures in a plate. A hawser is then attached to a bar rigidly mounted between two parallel ribs on the top surface of the plate. When the hawser angle is higher than horizontal, a situation that Mazur envisions, the plate does not interact with the stakes to improve anchoring performance. Where the hawser is attached to a boat and the hawser slopes down from the anchor, i.e., the boat is significantly below the level of the anchor, the hawser can rub against the edge of the plate (FIG. 4) due to wave motion, causing the hawser to wear.
Lee et al., in U.S. Pat. No. 4,315,387 (1980), discloses a ground anchor stake device. It has of straight and curved tines, the two sets of tines being pivotally attached to each other. The straight tines are first driven into the ground at an angle, and the curved tines are pressed into the ground in front of the straight tines.
Kinsey, in U.S. Pat. No. 4,679,369 (1985), describes a device using a series of stakes driven into the ground at the same angle. The stakes are made equidistant by using a series of spacer bars, each with a hole at each end to fit around a stake. Adjacent spacer bars are separated by a cylindrical collar fitted around their common spike. The final stake also has a collar, flat against the ground, to which a hawser is attached. Assembly of the device is somewhat complex. Its holding power is mainly due to the use of several stakes. The spacer bar arrangement assures that the force exerted by the hawser is distributed equally among the stakes. There is a potential for losing or misplacing the various components if they are stored carelessly. Speed of installation and retraction, especially when several stakes are to be used in series, could be an issue.
Wendling, in U.S. Pat. No. 4,800,843 (1987), discloses a multi-stake tether with a swiveling top for tethering animals. This swiveling capability is not relevant to mooring and anchoring applications. Horowitz, in U.S. Pat. No. 4,936,194 (1989), discloses a simple boat-tying stake with a handle. Mestas, in U.S. Pat. No. 4,960,064 (1989), discloses a single stake boat ground anchor, including a small underground-deployable stabilizing ‘wing’ to increase resistance to being pulled out of the ground. The wing, however, is small, relative to the stake, so that it lacks optimal stabilizing effect. Roberts, in U.S. Pat. No. 5,243,795 (1991), discloses a staking device for aircraft securement. Three stakes are driven into the ground at various angles through bores in a cylindrical hub which sits on the ground. The hub has a loop affixed to its top, allowing a hawser to be tied to it. The stakes are driven through the hub, fixing the block in place. Travioli, in U.S. Pat. No. 5,460,112 (1993), discloses a rack intended to be placed on a beach near the waterline, to which a boat's bow is attached. The rack has a single sand-embedded plate. The whole assembly is somewhat complex and ungainly, and if the roller (FIG. 2) becomes jammed, it could abrade the bottom of the boat due to lateral wave motion. A separate tool, such as a rock or hammer, is needed to drive the plate into the ground since the plate (FIG. 2) has a narrow upper lip to which it is not convenient to apply hand or foot pressure.
Other sand or beach devices are known.
Peterson, in U.S. Pat. No. 2,662,342 (1953), discloses a lawn border edging component. While comprising three tines and a plate, it contains no attachment means for a hawser, since it is not intended to be used as an anchoring device of any kind but rather as an in-ground guide track for lawn edge trimming tools. Pitt, in U.S. Pat. No. 4,334,661 (1978), shows another drink holder. Unlike Auspos, it has a plate perpendicular to its single spike to provide support for the user's drink. While it could be used as a ground anchor, the plate is too small to provide any compressive force onto the soil and is not intended to withstand horizontal forces such as are exerted by a hawser attached to a boat or other moored object.
Finally, Hart, in U.S. Pat. No. 5,360,189 (1994), discloses an outdoor bag holding stand. It has two tines that are pressed into the ground, but the presence of cross-members 13 and 16 allows the upright tines to be inserted to only a fraction of their length into the ground. Even if it were used as an anchoring device, the long lever arm constituted by the portion of the tines above ground would cause it to be easily pulled out by a horizontal force upon its upper loop 11. It works as a bag holder in which the forces on the upper loop are mostly downward, rather than horizontal as in the anchoring application.